**13. Key features and biomarker of Capgras syndrome**

Low platelet monoamine oxidase (MAO) activity is a biochemical abnormality which is present in some psychiatric disease. Some authors suggested that the low platelet MAO activity might be proposed as a potential biochemical marker of CS. It is also thought that reduced *monoamine oxidase* activity in primary psychiatric patients with CS may give a piece of information to the pathogenetic mechanism underlying the reported cases of CS in organic patients without a primary behavioral disorder. However, study results show that platelet *monoamine oxidase* activity in patients with delusional misidentifications did not differ notably from that of schizophrenia and nonpsychiatric controls [41, 48].

The key features currently considered to be critical to the development of the Capgras delusion are as follows:


#### **14. Treatment considerations**

Delusion in CS should be treated timely because it can cause a dangerous condition [42]. However, there are no guidelines to assist clinicians to care for patients presenting with CS in selecting complementary examinations to be performed or in selecting treatment [7]. Likewise, the symptoms of DMS are very refractory to treatment despite various interventions including psychotherapy and pharmacotherapy approaches [19]. The CS like other DMSs is known to develop similar to the comorbid disorder that they accompany, disappearing after remission even though it is not unusual for them to continue after the disappearance of the comorbid disorder [7]. Thus, treatment of the underlying neurological or psychiatric conditions may not lead to remission of CS [27]. The presence of depersonalization, derealization or visual-perceptual disturbances, and other comorbidities may influence the treatment of CS [47]. The syndrome has been linked to dopaminergic overactivity, and serotonin abnormality has been implicated in some but not all studies. Similarly, reduced platelet monoamine oxidase activity has been noted by some but not by others [17]. According to the results of the case studies in the literature, CS patients are sometimes responsive to typical and atypical antipsychotics such as olanzapine, risperidone, quetiapine, sulpiride, trifluoperazine, and pimozide [19]. Pharmacological treatment of

**129**

*What is Capgras Syndrome? Diagnosis and Treatment Approach*

CS is based on antipsychotics, antidepressants, anticonvulsant, and benzodiazepines considering patient needs and characteristics, but no control trials are available [49]. In the literature, there have been reported cases with a diagnosis of organic or functional delusional disorder associated with CS whose DMS responded well to pimozide that is well known for the treatment of monosymptomatic delusional disorders [49]. Experience with the new generation of atypical antipsychotics for the treatment of CS is quite limited. Although for patients manifesting any psychotic disorder, atypical antipsychotics are usually recommended because of the reduced risk of adverse effects [6, 47]. A crucial point of a case report is the positive outcome in response to antipsychotic medication [olanzapine] [49]. The combination of antipsychotic drug therapy and selective serotonin reuptake inhibitor (SSRI) may produce a positive

A case report also suggested the use of clorazepate which is benzodiazepine. In this case report, in addition to the antipsychotic properties of clorazepate, its anticonvulsant properties were also utilized in CS patient with the suggestion of some researches that found an over 90% incidence of electroencephalographic abnormalities in CS patients [26]. According to the results of the case studies, it showed a positive outcome in a patient with CS after treatment with mirtazapine that is also a serotonin 2A receptor antagonist, which could potentially afford its antipsychotic effects resulting in significantly decreasing the symptoms of CS

With patients who have progressive dementia, such as dementia with Lewy bodies, in which misidentification syndromes are common occurred, cholinesterase

Electroconvulsive therapy (ECT) has been reported to benefit either alone or in conjunction with antipsychotics, mood stabilizer, or antidepressant medication in patients with CS. It has been suggested that ECT provides permanent effective

Psychotherapy may be beneficial in the treatment of selected patients with CS in order to reform the patient's relationship with his family. The psychoanalytic theories show that the emotions which the patient experiences in regard to the people with whom he is confronted are transferred to the imposters, and therefore, in this way from a safe delusional distance, the patient gives himself to refuse them without guilt, sometimes manifesting an aggressive behaviour toward them [21, 22]. It has been shown that group psychotherapy may also be beneficial by becoming less prone to feel hostile toward others, thereby weakening the delusional misidentification process for psychotic patients with DMS [40]. Cognitive behavioural therapy (CBT) may be a utilized form of psychotherapy intervention in some cases

inhibitors have demonstrated benefit to reduce psychiatric symptoms [6].

by assisting the patient to overcome the delusional beliefs [21, 22].

It is quite common in cases of delusion for his/her family members of the deluded person to be concerned about the delusion and to try to get rid of it by constantly challenging it [43]. It may be beneficial to know that just as an impairment in the interpersonal relationship between the patient and the object may occur before the onset of the delusion, an amelioration in this relationship is an essential factor in the amelioration of symptoms. Therefore treatment must include helping the partner or person implicated to gain insight and perhaps change their attitude

CS is a different neuropsychiatric symptom of interest to researchers over the past century. No approved questionnaires focus on CS. While noting that

*DOI: http://dx.doi.org/10.5772/intechopen.91153*

outcome in patients with CS [15].

control of CS [42, 47, 49].

toward the patient [29].

**15. Conclusion**

[19, 27].

#### *What is Capgras Syndrome? Diagnosis and Treatment Approach DOI: http://dx.doi.org/10.5772/intechopen.91153*

*Anxiety Disorders - The New Achievements*

Many patients with CS also present with medical illnesses of organic etiologies, associated with delusional misidentification; these patients may respond well to treatment of the medical condition underlying the onset of CS [47]. The syndrome should be differentiated from the quite common false recognitions which occur in confusional states and the transient misidentifications encountered in mania [8]. For this purpose, ending with a complete mental status examination, as well as thorough testing of cognition, is important. Neuropsychological testing and neuroimaging are often indicated. Clinicians should clarify the nature of the underlying psychiatric illness [45].

Low platelet monoamine oxidase (MAO) activity is a biochemical abnormality which is present in some psychiatric disease. Some authors suggested that the low platelet MAO activity might be proposed as a potential biochemical marker of CS. It is also thought that reduced *monoamine oxidase* activity in primary psychiatric patients with CS may give a piece of information to the pathogenetic mechanism underlying the reported cases of CS in organic patients without a primary behavioral disorder. However, study results show that platelet *monoamine oxidase* activity in patients with delusional misidentifications did not differ notably from that of

The key features currently considered to be critical to the development of the

• There is an abnormal perceptual experience that is a prerequisite for the

• This perceptual experience is accompanied by a paranoid which leads to

• The loss of normal response to known faces occurs in the context of more

Delusion in CS should be treated timely because it can cause a dangerous condition [42]. However, there are no guidelines to assist clinicians to care for patients presenting with CS in selecting complementary examinations to be performed or in selecting treatment [7]. Likewise, the symptoms of DMS are very refractory to treatment despite various interventions including psychotherapy and pharmacotherapy approaches [19]. The CS like other DMSs is known to develop similar to the comorbid disorder that they accompany, disappearing after remission even though it is not unusual for them to continue after the disappearance of the comorbid disorder [7]. Thus, treatment of the underlying neurological or psychiatric conditions may not lead to remission of CS [27]. The presence of depersonalization, derealization or visual-perceptual disturbances, and other comorbidities may influence the treatment of CS [47]. The syndrome has been linked to dopaminergic overactivity, and serotonin abnormality has been implicated in some but not all studies. Similarly, reduced platelet monoamine oxidase activity has been noted by some but not by others [17]. According to the results of the case studies in the literature, CS patients are sometimes responsive to typical and atypical antipsychotics such as olanzapine, risperidone, quetiapine, sulpiride, trifluoperazine, and pimozide [19]. Pharmacological treatment of

misattribution of the abnormal perceptual experience.

generalized derealization-depersonalization [41].

**13. Key features and biomarker of Capgras syndrome**

schizophrenia and nonpsychiatric controls [41, 48].

Capgras delusion are as follows:

**14. Treatment considerations**

delusion.

**128**

CS is based on antipsychotics, antidepressants, anticonvulsant, and benzodiazepines considering patient needs and characteristics, but no control trials are available [49]. In the literature, there have been reported cases with a diagnosis of organic or functional delusional disorder associated with CS whose DMS responded well to pimozide that is well known for the treatment of monosymptomatic delusional disorders [49]. Experience with the new generation of atypical antipsychotics for the treatment of CS is quite limited. Although for patients manifesting any psychotic disorder, atypical antipsychotics are usually recommended because of the reduced risk of adverse effects [6, 47]. A crucial point of a case report is the positive outcome in response to antipsychotic medication [olanzapine] [49]. The combination of antipsychotic drug therapy and selective serotonin reuptake inhibitor (SSRI) may produce a positive outcome in patients with CS [15].

A case report also suggested the use of clorazepate which is benzodiazepine. In this case report, in addition to the antipsychotic properties of clorazepate, its anticonvulsant properties were also utilized in CS patient with the suggestion of some researches that found an over 90% incidence of electroencephalographic abnormalities in CS patients [26]. According to the results of the case studies, it showed a positive outcome in a patient with CS after treatment with mirtazapine that is also a serotonin 2A receptor antagonist, which could potentially afford its antipsychotic effects resulting in significantly decreasing the symptoms of CS [19, 27].

With patients who have progressive dementia, such as dementia with Lewy bodies, in which misidentification syndromes are common occurred, cholinesterase inhibitors have demonstrated benefit to reduce psychiatric symptoms [6].

Electroconvulsive therapy (ECT) has been reported to benefit either alone or in conjunction with antipsychotics, mood stabilizer, or antidepressant medication in patients with CS. It has been suggested that ECT provides permanent effective control of CS [42, 47, 49].

Psychotherapy may be beneficial in the treatment of selected patients with CS in order to reform the patient's relationship with his family. The psychoanalytic theories show that the emotions which the patient experiences in regard to the people with whom he is confronted are transferred to the imposters, and therefore, in this way from a safe delusional distance, the patient gives himself to refuse them without guilt, sometimes manifesting an aggressive behaviour toward them [21, 22]. It has been shown that group psychotherapy may also be beneficial by becoming less prone to feel hostile toward others, thereby weakening the delusional misidentification process for psychotic patients with DMS [40]. Cognitive behavioural therapy (CBT) may be a utilized form of psychotherapy intervention in some cases by assisting the patient to overcome the delusional beliefs [21, 22].

It is quite common in cases of delusion for his/her family members of the deluded person to be concerned about the delusion and to try to get rid of it by constantly challenging it [43]. It may be beneficial to know that just as an impairment in the interpersonal relationship between the patient and the object may occur before the onset of the delusion, an amelioration in this relationship is an essential factor in the amelioration of symptoms. Therefore treatment must include helping the partner or person implicated to gain insight and perhaps change their attitude toward the patient [29].
